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Ma QX, Arneodo A, Ding GH, Argoul F. Dynamical study of Νaν channel excitability under mechanical stress. BIOLOGICAL CYBERNETICS 2017; 111:129-148. [PMID: 28233067 DOI: 10.1007/s00422-017-0712-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Accepted: 02/06/2017] [Indexed: 06/06/2023]
Abstract
Alteration of [Formula: see text] channel functions (channelopathies) has been encountered in various hereditary muscle diseases. [Formula: see text] channel mutations lead to aberrant excitability in skeletal muscle myotonia and paralysis. In general, these mutations disable inactivation of the [Formula: see text] channel, producing either repetitive action potential firing (myotonia) or electrical dormancy (flaccid paralysis) in skeletal muscles. These "sick-excitable" cell conditions were shown to correlate with a mechanical stretch-driven left shift of the conductance factors of the two gating mechanisms of a fraction of [Formula: see text] channels, which make them firing at inappropriate hyperpolarised (left-shifted) voltages. Here we elaborate on a variant of the Hodgkin-Huxley model that includes a stretch elasticity energy component in the activation and inactivation gate kinetic rates. We show that this model reproduces fairly well sick-excitable cell behaviour and can be used to predict the parameter domains where aberrant excitability or paralysis may occur. By allowing us to separate the incidences of activation and inactivation gate impairments in [Formula: see text] channel excitability, this model could be a strong asset for diagnosing the origin of excitable cell disorders.
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Affiliation(s)
- Q X Ma
- Shanghai Key Laboratory for Acupuncture Mechanism and Acupoint Function, Department of Aeronautics and Astronautics, Fudan University, Shanghai, 200433, China
| | - A Arneodo
- LOMA, CNRS, UMR 5798, Université de Bordeaux, 51 Cours de la Libération, 33405, Talence, France
- Laboratoire de Physique, ENS Lyon, CNRS UMR5672, Université de Lyon, 46 Allée d'Italie, 69364, Lyon, France
| | - G H Ding
- Shanghai Key Laboratory for Acupuncture Mechanism and Acupoint Function, Department of Aeronautics and Astronautics, Fudan University, Shanghai, 200433, China
| | - F Argoul
- LOMA, CNRS, UMR 5798, Université de Bordeaux, 51 Cours de la Libération, 33405, Talence, France.
- Laboratoire de Physique, ENS Lyon, CNRS UMR5672, Université de Lyon, 46 Allée d'Italie, 69364, Lyon, France.
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Borges AS, Barbosa JD, Resende LAL, Mota LSLS, Amorim RM, Carvalho TL, Garcia JF, Oliveira-Filho JP, Oliveira CMC, Souza JES, Winand NJ. Clinical and molecular study of a new form of hereditary myotonia in Murrah water buffalo. Neuromuscul Disord 2013; 23:206-13. [PMID: 23339992 DOI: 10.1016/j.nmd.2012.11.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Revised: 11/04/2012] [Accepted: 11/12/2012] [Indexed: 10/27/2022]
Abstract
Hereditary myotonia caused by mutations in CLCN1 has been previously described in humans, goats, dogs, mice and horses. The goal of this study was to characterize the clinical, morphological and genetic features of hereditary myotonia in Murrah buffalo. Clinical and laboratory evaluations were performed on affected and normal animals. CLCN1 cDNA and the relevant genomic region from normal and affected animals were sequenced. The affected animals exhibited muscle hypertrophy and stiffness. Myotonic discharges were observed during EMG, and dystrophic changes were not present in skeletal muscle biopsies; the last 43 nucleotides of exon-3 of the CLCN1 mRNA were deleted. Cloning of the genomic fragment revealed that the exclusion of this exonic sequence was caused by aberrant splicing, which was associated with the presence of a synonymous SNP in exon-3 (c.396C>T). The mutant allele triggered the efficient use of an ectopic 5' splice donor site located at nucleotides 90-91 of exon-3. The predicted impact of this aberrant splicing event is the alteration of the CLCN1 translational reading frame, which results in the incorporation of 24 unrelated amino acids followed by a premature stop codon.
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Affiliation(s)
- Alexandre S Borges
- Department of Veterinary Clinical Science, College of Veterinary Medicine and Animal Science, Univ Estadual Paulista (UNESP), Botucatu, Brazil.
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Kiesewetter IS, Tipold A, Baumgärtner W, Schenk HC. Potassium-aggravated muscle stiffness in 12 cats. J Am Vet Med Assoc 2011; 238:1026-31. [PMID: 21492046 DOI: 10.2460/javma.238.8.1026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
CASE DESCRIPTION 12 European shorthair cats (6 males and 6 females; age range, 2 months to 3 years) from 1 household were evaluated for clinical signs of recurrent and progressive muscle spasticity. Genetic relationships among the cats were suspected but were not known. CLINICAL FINDINGS Physical examination of all cats revealed a thin to mildly emaciated body condition and signs of suppurative rhinitis. Results of neurologic evaluations revealed no abnormalities in any cats at rest, but exercise- and stress-induced episodes of muscle spasticity were observed. Results of hematologic (7/12 cats) and CSF (4) analysis, diagnostic imaging (including radiography [7] and magnetic resonance imaging [4]), electromyography (4), motor nerve conduction tests (4), screening for metabolic storage diseases (4), provocation tests via exercise in a cold (4°C [39.2°F]) environment (7), and gross pathological and histologic examination (5) revealed no abnormalities that could potentially explain the clinical signs. However, consumption of a potassium-enriched diet resulted in severe aggravation of clinical signs in 7 of 7 cats, leading to a diagnosis of potassium-aggravated muscle stiffness. TREATMENT AND OUTCOME 5 cats were euthanized after initial examination because of poor physical condition and severe clinical signs. Spasticity in the 7 remaining cats was improved during a 6-week follow-up period as they reduced their own activity. Further investigation and treatment were declined. CLINICAL RELEVANCE Channelopathies are rarely recognized diseases in domestic animals. In addition to conventional diagnostic evaluation methods, provocation tests in a clinical environment can be used in the assessment of channelopathies.
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Affiliation(s)
- Iris S Kiesewetter
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover Foundation, Germany
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Fialho D, Schorge S, Pucovska U, Davies NP, Labrum R, Haworth A, Stanley E, Sud R, Wakeling W, Davis MB, Kullmann DM, Hanna MG. Chloride channel myotonia: exon 8 hot-spot for dominant-negative interactions. Brain 2007; 130:3265-74. [DOI: 10.1093/brain/awm248] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- D. Fialho
- Department of Molecular Neuroscience and Department of Clinical and Experimental Epilepsy, MRC Centre for Neuromuscular Disease, Institute of Neurology, UCL and National Hospital for Neurology, Queen Square, London and 2Department of Neurology, Muscle and Nerve Centre, Queen Elizabeth Hospital, University of Birmingham NHS Trust, Birmingham, UK
| | - S. Schorge
- Department of Molecular Neuroscience and Department of Clinical and Experimental Epilepsy, MRC Centre for Neuromuscular Disease, Institute of Neurology, UCL and National Hospital for Neurology, Queen Square, London and 2Department of Neurology, Muscle and Nerve Centre, Queen Elizabeth Hospital, University of Birmingham NHS Trust, Birmingham, UK
| | - U. Pucovska
- Department of Molecular Neuroscience and Department of Clinical and Experimental Epilepsy, MRC Centre for Neuromuscular Disease, Institute of Neurology, UCL and National Hospital for Neurology, Queen Square, London and 2Department of Neurology, Muscle and Nerve Centre, Queen Elizabeth Hospital, University of Birmingham NHS Trust, Birmingham, UK
| | - N. P. Davies
- Department of Molecular Neuroscience and Department of Clinical and Experimental Epilepsy, MRC Centre for Neuromuscular Disease, Institute of Neurology, UCL and National Hospital for Neurology, Queen Square, London and 2Department of Neurology, Muscle and Nerve Centre, Queen Elizabeth Hospital, University of Birmingham NHS Trust, Birmingham, UK
| | - R. Labrum
- Department of Molecular Neuroscience and Department of Clinical and Experimental Epilepsy, MRC Centre for Neuromuscular Disease, Institute of Neurology, UCL and National Hospital for Neurology, Queen Square, London and 2Department of Neurology, Muscle and Nerve Centre, Queen Elizabeth Hospital, University of Birmingham NHS Trust, Birmingham, UK
| | - A. Haworth
- Department of Molecular Neuroscience and Department of Clinical and Experimental Epilepsy, MRC Centre for Neuromuscular Disease, Institute of Neurology, UCL and National Hospital for Neurology, Queen Square, London and 2Department of Neurology, Muscle and Nerve Centre, Queen Elizabeth Hospital, University of Birmingham NHS Trust, Birmingham, UK
| | - E. Stanley
- Department of Molecular Neuroscience and Department of Clinical and Experimental Epilepsy, MRC Centre for Neuromuscular Disease, Institute of Neurology, UCL and National Hospital for Neurology, Queen Square, London and 2Department of Neurology, Muscle and Nerve Centre, Queen Elizabeth Hospital, University of Birmingham NHS Trust, Birmingham, UK
| | - R. Sud
- Department of Molecular Neuroscience and Department of Clinical and Experimental Epilepsy, MRC Centre for Neuromuscular Disease, Institute of Neurology, UCL and National Hospital for Neurology, Queen Square, London and 2Department of Neurology, Muscle and Nerve Centre, Queen Elizabeth Hospital, University of Birmingham NHS Trust, Birmingham, UK
| | - W. Wakeling
- Department of Molecular Neuroscience and Department of Clinical and Experimental Epilepsy, MRC Centre for Neuromuscular Disease, Institute of Neurology, UCL and National Hospital for Neurology, Queen Square, London and 2Department of Neurology, Muscle and Nerve Centre, Queen Elizabeth Hospital, University of Birmingham NHS Trust, Birmingham, UK
| | - M. B. Davis
- Department of Molecular Neuroscience and Department of Clinical and Experimental Epilepsy, MRC Centre for Neuromuscular Disease, Institute of Neurology, UCL and National Hospital for Neurology, Queen Square, London and 2Department of Neurology, Muscle and Nerve Centre, Queen Elizabeth Hospital, University of Birmingham NHS Trust, Birmingham, UK
| | - D. M. Kullmann
- Department of Molecular Neuroscience and Department of Clinical and Experimental Epilepsy, MRC Centre for Neuromuscular Disease, Institute of Neurology, UCL and National Hospital for Neurology, Queen Square, London and 2Department of Neurology, Muscle and Nerve Centre, Queen Elizabeth Hospital, University of Birmingham NHS Trust, Birmingham, UK
| | - M. G. Hanna
- Department of Molecular Neuroscience and Department of Clinical and Experimental Epilepsy, MRC Centre for Neuromuscular Disease, Institute of Neurology, UCL and National Hospital for Neurology, Queen Square, London and 2Department of Neurology, Muscle and Nerve Centre, Queen Elizabeth Hospital, University of Birmingham NHS Trust, Birmingham, UK
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Felix R. Calcium channelopathies. Neuromolecular Med 2007; 8:307-18. [PMID: 16775382 DOI: 10.1385/nmm:8:3:307] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2005] [Revised: 11/30/1999] [Accepted: 01/20/2006] [Indexed: 11/11/2022]
Abstract
Intracellular calcium ([Ca2+]i) is highly regulated in eukaryotic cells. The free [Ca2+]i is approximately four orders of magnitude less than that in the extracellular environment. It is, therefore, an electrochemical gradient favoring Ca2+ entry, and transient cellular activation increasing Ca2+ permeability will lead to a transient increase in [Ca2+]i. These transient rises of [Ca2+]i trigger or regulate diverse intracellular events, including metabolic processes, muscle contraction, secretion of hormones and neurotransmitters, cell differentiation, and gene expression. Hence, changes in [Ca2+]i act as a second messenger system coordinating modifications in the external environment with intracellular processes. Notably, information on the molecular genetics of the membrane channels responsible for the influx of Ca2+ ions has led to the discovery that mutations in these proteins are linked to human disease. Ca2+ channel dysfunction is now known to be the basis for several neurological and muscle disorders such as migraine, ataxia, and periodic paralysis. In contrast to other types of genetic diseases, Ca2+ channelopathies can be studied with precision by electrophysiological methods, and in some cases, the results have been highly rewarding with a biophysical phenotype that correlates with the ultimate clinical phenotype. This review outlines recent advances in genetic, molecular, and pathophysiological aspects of human Ca2+ channelopathies.
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Affiliation(s)
- Ricardo Felix
- Department of Cell Biology, Center for Research and Advanced Studies, National Polytechnic Institute (Cinvestav-IPN), Mexico City, Mexico.
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Abstract
Several neurological diseases-including neuromuscular disorders, movement disorders, migraine, and epilepsy-are caused by inherited mutations of ion channels. The list of these "channelopathies" is expanding rapidly, as is the phenotypic range associated with each channel. At present the best understood channelopathies are those that affect muscle-fibre excitability. These channelopathies produce a range of disorders which include: periodic paralysis, myotonias, malignant hyperthermia, and congenital myasthenic syndromes. By contrast, the mechanisms of diseases caused by mutations of ion channels that are expressed in neurons are less well understood. However, as for the muscle channelopathies, a striking feature is that many neuronal channelopathies cause paroxysmal symptoms. This review summarises the clinical features of the known neurological channelopathies, within the context of the functions of the individual ion channels.
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Affiliation(s)
- Dimitri M Kullmann
- Institute of Neurology, University College London, and the National Hospital for Neurology and Neurosurgery, London, UK.
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